net: bcmgenet: prevent duplicate calls of bcmgenet_dma_teardown

When bcmgenet_dma_teardown is called from bcmgenet_fini_dma it ends
up getting called twice from the bcmgenet_close and bcmgenet_suspend
functions (once directly and once inside the bcmgenet_fini_dma call).

This commit removes the call from bcmgenet_fini_dma and ensures that
bcmgenet_dma_teardown is called before bcmgenet_fini_dma in all paths
of execution.

Fixes: 4a0c081e ("net: bcmgenet: call bcmgenet_dma_teardown in bcmgenet_fini_dma")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>